Biogenic volatile organic compound emissions from Willow trees

Abstract: In August 2012, emissions of biogenic volatile organic compounds (BVOCs) from willow (Salix) trees were measured in Lund, southern Sweden. Sweden has more than 16000 ha of short rotation willow plantations for biofuel production and willow trees are suspected to emit substantial amounts of BVOC to the atmosphere. BVOC emission measurements were carried out on two Salix fragilis trees and one Salix phylicifolia tree. The measurements were conducted using a dynamic flow through chamber covered with Teflon film. Salix trees were found to emit large amounts of isoprene. Especially Salix phylicifolia emitted 98% isoprene of total BVOC emission, whereas Salix fragilis trees released about 85% of the total BVOC mass as isoprene. Apart from isoprene, willow trees were found to emit significant amounts of ocimene as well. Emission rates of different BVOCs were found to vary between different individuals of the same species of willow trees as well as between the subspecies of willow trees. Emissions of BVOCs were detected to depend on temperature and photosynthetically active radiation. Isoprene emission potential for Salix phylicifolia was 56.4 µg g-1dw h-1 whereas 16.9 µg g-1dw h-1 and 44.4 µg g-1dw h-1 were measured for the Salix fragilis trees.